Semiconductor device and semiconductor device fabrication method

ABSTRACT

A semiconductor device includes a printed circuit board in a peripheral portion of a housing portion of a case in which a laminated substrate is housed. A terminal block holding control terminals from which control signals are outputted to the printed circuit board is disposed over the printed circuit board. A gate electrode of a semiconductor chip and the printed circuit board are electrically connected by a wire.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation of copending U.S. application Ser. No. 15/176,211, filed on Jun. 8, 2016, and allowed on Apr. 23, 2019, and is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2015-132789, filed on Jul. 1, 2015, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The embodiments discussed herein are related to a semiconductor device and a semiconductor device fabrication method.

2. Background of the Related Art

Power semiconductor modules (semiconductor devices) include semiconductor chips, such as insulated gate bipolar transistors (IGBTs), metal oxide semiconductor field effect transistors (MOSFETs), and free wheeling diodes (FWDs), and are widely used as power converters.

With such semiconductor devices, a laminated substrate including an insulating board and a circuit pattern made of copper foil which is formed on the insulating board is housed in a case. The above semiconductor chips are disposed over the copper foil. Furthermore, the laminated substrate and the semiconductor chips in the case are wired. Electrodes of the semiconductor chips are electrically connected by wires and the electrodes of the semiconductor chips and external electrode terminals are electrically connected by wires. These components in the case are sealed with resin (see, for example, Japanese Laid-open Patent Publication No. 2000-323646).

By the way, with improvement in the function of a semiconductor chip included in a semiconductor device, the number of wirings per element of a control signal system tends to increase. Accordingly, in order to prevent wirings in a case of a semiconductor device from becoming complicated, the following method, for example, is tried for simplifying wiring connection. A circuit pattern and the like are formed over a laminated substrate and the circuit pattern is used for wiring routing.

However, even if a circuit pattern is used, an increase in the number of wirings leads to complicated wiring routing. As a result, assemble-ability deteriorates and man-hours needed for wiring work increase. Furthermore, with wirings of a control signal system a magnetic field or the like produced at switching time has an influence on the characteristics of a product, depending on a routing method. As a result, a malfunction may occur.

SUMMARY OF THE INVENTION

According to an aspect, there is provided a semiconductor device including a laminated substrate including an insulating board and a circuit board disposed over a front surface of the insulating board, a semiconductor chip disposed over the circuit board, a case having a housing area for housing the laminated substrate and the semiconductor chip, a terminal block having a first surface and a second surface opposite the first surface and holding external connection terminals protruding from the first surface and the second surface, and a printed circuit board having a first principal plane and a second principal plane opposite the first principal plane, disposed over a periphery of the housing area, held on a second surface side of the terminal block, electrically connected to a control electrode of the semiconductor chip by a connecting member, and connected to the external connection terminals.

The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a semiconductor device according to a first embodiment;

FIG. 2 is a flow chart of a method for fabricating the semiconductor device according to the first embodiment;

FIG. 3 is a perspective view which illustrates a state in which parts are mounted over an insulating substrate of the semiconductor device according to the first embodiment;

FIG. 4 is a perspective view of terminal blocks of the semiconductor device according to the first embodiment;

FIG. 5 is a perspective view of another example of terminal blocks of the semiconductor device according to the first embodiment;

FIG. 6 is a perspective view of a printed circuit board and the terminal blocks of the semiconductor device according to the first embodiment (part 1);

FIG. 7 is a perspective view of the printed circuit board and the terminal blocks of the semiconductor device according to the first embodiment (part 2);

FIG. 8 is a fragmentary sectional view of the printed circuit board and a laminated substrate of the semiconductor device according to the first embodiment;

FIG. 9 is a plan view of a case of the semiconductor device according to the first embodiment;

FIG. 10 is a rear view of the case of the semiconductor device according to the first embodiment;

FIG. 11 is a circuit diagram which illustrates circuit structure in the semiconductor device according to the first embodiment;

FIG. 12 is a plan view of a semiconductor device taken as an example for reference;

FIG. 13 is a perspective view of a semiconductor device according to a second embodiment;

FIG. 14 is a flow chart of a method for fabricating the semiconductor device according to the second embodiment;

FIG. 15 is a plan view of a bus bar block of the semiconductor device according to the second embodiment; and

FIG. 16 is a plan view of a case of the semiconductor device according to the second embodiment in which insulating substrates are housed.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments will now be described with reference to the accompanying drawings, wherein like reference numerals refer to like elements throughout.

First Embodiment

First a semiconductor device according to a first embodiment will be described by the use of FIG. 1.

FIG. 1 is a perspective view of a semiconductor device according to a first embodiment.

A semiconductor device 100 includes a case 110 and laminated substrates 140 housed in housing portions 112 a, 112 b, and 112 c of the case 110.

With the semiconductor device 100, a positive electrode is connected to P terminals 113 a, 113 b, and 113 c and a negative electrode is connected to N terminals 114 a, 114 b, and 114 c. A control signal is applied to each of control terminals 121 and 131. An output corresponding to a control signal is obtained from each of a U terminal 115 a, a V terminal 115 b and a W terminal 115 c.

The details of the case 110 included in the above semiconductor device 100 and the laminated substrates 140 housed in the case 110 will be described later.

A method for fabricating the semiconductor device 100 will now be described by the use of FIG. 2.

FIG. 2 is a flow chart of a method for fabricating the semiconductor device according to the first embodiment.

(Step S11) Printed circuit boards 119 a and 119 b and terminal blocks 120 and 130 are prepared (step S11 a). Furthermore, the laminated substrates 140 are prepared (step S11 b). In step S11 a, control terminals 121 and 131 of the terminal blocks 120 and 130, respectively, are press-fitted in the printed circuit boards 119 a and 119 b to hold the printed circuit boards 119 a and 119 b on an under surface side of the terminal blocks 120 and 130.

The laminated substrate 140 will now be described by the use of FIG. 3.

FIG. 3 is a perspective view which illustrates a state in which parts are mounted over an insulating substrate of the semiconductor device according to the first embodiment.

The laminated substrate 140 includes a radiation plate (not illustrated) made of, for example, copper or the like and disposed over an under surface of an insulating substrate 141 and circuit boards 142 a and 142 b made of, for example, copper foil or the like and disposed over an upper surface of the insulating substrate 141.

For example, a conductive terminal 143 a made of copper is disposed on the lower side of the circuit board 142 a in FIG. 3 and (collector electrodes of) semiconductor chips 144 a, 144 b and 144 c are aligned over the circuit board 142 a with solder therebetween. Furthermore, a straight lead frame 145 a is disposed with solder therebetween over emitter electrodes of the aligned semiconductor chips 144 a, 144 b and 144 c. As a result, the emitter electrodes of the semiconductor chips 144 a, 144 b and 144 c are electrically connected to one another.

For example, a conductive terminal 143 b made of copper is disposed on the upper side of the circuit board 142 b in FIG. 3 and (collector electrodes of) semiconductor chips 146 a, 146 b and 146 c are aligned over the circuit board 142 b with solder therebetween. Furthermore, a straight lead frame 145 b is disposed with solder therebetween over emitter electrodes of the aligned semiconductor chips 146 a, 146 b and 146 c. As a result, the emitter electrodes of the semiconductor chips 146 a, 146 b and 146 c are electrically connected to one another.

An IGBT, a MOSFET, a FWD, or the like is used as the semiconductor chip 144 a, 144 b, 144 c, 146 a, 146 b or 146 c. In the example of FIG. 3, a reverse conducting IGBT (RC-IGBT) is used as, for example, the semiconductor chip 144 a. In addition to main electrodes (emitter electrodes and the collector electrodes), the semiconductor chips 144 a, 144 b, 144 c, 146 a, 146 b and 146 c have a plurality of control electrodes 144 ac, 144 bc, 144 cc, 146 ac, 146 bc and 146 cc, respectively, connected to gate terminals, sense terminals, and chip temperature measurement terminals.

In the example of FIG. 3, the emitter electrodes of the semiconductor chips 144 a, 144 b and 144 c are connected by the lead frame 145 a. However, the emitter electrodes of the semiconductor chips 144 a, 144 b and 144 c may be connected by another method. That is to say, the emitter electrodes of the semiconductor chips 144 a, 144 b and 144 c may be connected by a wire made of aluminum or the like. Similarly, the emitter electrodes of the semiconductor chips 146 a, 146 b and 146 c may be connected by a wire.

Next, the terminal blocks 120 and 130 will be described by the use of FIGS. 4 through 7.

FIG. 4 is a perspective view of the terminal blocks of the semiconductor device according to the first embodiment. FIG. 5 is a perspective view of another example of terminal blocks of the semiconductor device according to the first embodiment.

Furthermore, each of FIGS. 6 and 7 is a perspective view of the printed circuit board and the terminal blocks of the semiconductor device according to the first embodiment. In FIGS. 6 and 7, the terminal blocks 120 and 130 are disposed over the printed circuit board 119 a.

As illustrated in FIG. 4, the terminal blocks 120 and 130 are formed by integrally molding the control terminals (external connection terminals) 121 and 131, respectively, by the use of resin and have an almost cuboid shape. There are spaces 122 and 132 each defined by two protrusions on the under surface (second surface) side of the terminal blocks 120 and 130 respectively. The under surfaces of the terminal blocks 120 and 130 are opposite the printed circuit board 119 a. The spaces 122 and 132 pierce the terminal blocks 120 and 130, respectively, from a front side to a back side in FIG. 4. Furthermore, level difference portions 123 and 133 are formed on facing surfaces of the terminal blocks 120 and 130 respectively. A terminal block 150 illustrated in FIG. 5 is formed by integrally molding control terminals 151 and the control terminals 151 protrude from upper and under surfaces of the terminal block 150. Each of the terminal blocks 120 and 130 may have a resin body like that of the terminal block 150 having a simple cuboid shape.

The above terminal blocks 120 and 130 hold a plurality of control terminals 121 and 131 respectively. Each control terminal 121 or each control terminal 131 has a structure in which both end portions are thicker than a body portion. The terminal blocks 120 and 130 hold the body portions of the above control terminals 121 and 131 respectively. Both end portions of the control terminals 121 and 131 which are thicker than the body portions protrude from upper surfaces (first surfaces) and the under surfaces (second surfaces) of the terminal blocks 120 and 130, respectively, illustrated in FIG. 4. As described later, lower end portions of the control terminals 121 and 131 which protrude on the under surface side of the terminal blocks 120 and 130, respectively, illustrated in FIG. 4 are press-fitted in through holes made in the printed circuit board 119 a. In FIG. 6, the control terminals 121 and 131 are arranged in two rows in the terminal blocks 120 and 130 respectively. As a result, compared with a case where control terminals 121 and 131 are arranged in a row, the number of the control terminals 121 and 131 held by the terminal blocks 120 and 130, respectively, is large. Furthermore, control terminals 121 and 131 may be arranged in three or more rows in the terminal blocks 120 and 130 respectively. By doing so, the number of control terminals 121 and 131 held by the terminal blocks 120 and 130, respectively, increases further. The terminal blocks 120 and 130 are disposed over an end portion of the printed circuit board 119 a.

The printed circuit board (circuit wiring board) 119 a used for forming the case 110 includes a wiring layer made of a conductive material and a board made of a highly heat-resistant material. A plurality of electrodes 119 a 1 electrically connected to the wiring layer are arranged over a front surface of the printed circuit board 119 a. The wiring layer may be a single layer, be formed over both surfaces of the printed circuit board 119 a, or have a multilayer structure. In addition, a plurality of through holes 119 a 2 which pierce from an upper surface (first principal plane) to an under surface (second principal plane) are made in the printed circuit board 119 a. As described later, the printed circuit board 119 a is integrally molded with the case 110. At this time resin used for forming the case 110 gets into the through holes 119 a 2. As a result, the printed circuit board 119 a easily adheres to the case 110. The plurality of through holes 119 a 2 are preferably arranged so that the plurality of electrodes 119 a 1 aligned will be sandwiched between them. The environs of the plurality of electrodes 119 a 1 are fixed with resin in the plurality of through holes 119 a 2. By doing so, the reliability of connection of wires 148 in a later step is improved.

Furthermore, a pattern made of, for example, copper may be formed over the back surface of the printed circuit board 119 a and irregularities may intentionally be formed on a surface of the pattern by blackening treatment. As a result, when the printed circuit board 119 a is integrally molded with the case 110, the irregularities over the back surface of the printed circuit board 119 a fit the case 110 and the printed circuit board 119 a easily adheres to the case 110. An allover pattern of a wiring layer on an under surface side may be used as a shield. A residue, such as resist, preferably is not left on the under surface of the printed circuit board 119 a.

The lower end portions of the control terminals 121 and 131 protruding from the under surfaces of the terminal blocks 120 and 130, respectively, are connected to the above printed circuit board 119 a by press-fitting and the terminal blocks 120 and 130 are disposed. As a result, the printed circuit board 119 a and the control terminals 121 and 131 are electrically connected. As illustrated in FIG. 7, the lower end portions of the control terminals 121 and 131 may be exposed or protrude on an under surface side of the printed circuit board 119 a.

If the lower end portions of the control terminals 121 and 131 are equal in thickness to the body portions of the control terminals 121 and 131, then the lower end portions of the control terminals 121 and 131 may be connected to the printed circuit board 119 a not by press-fitting but by soldering. In this case, the lower end portions of the control terminals 121 and 131 which pierce the printed circuit board 119 a (from the front surface side of the printed circuit board 119 a) are soldered on a back surface side of the printed circuit board 119 a. However, solder melts depending on temperature and molten solder may get into resin. In order to prevent molten solder from getting into resin, it is desirable to cover soldered portions of the control terminals 121 and 131 on the back surface side of the printed circuit board 119 a with epoxy resin and to cure the epoxy resin. Accordingly, when the control terminals 121 and 131 are fitted in the printed circuit board 119 a, it is desirable to perform press-fitting rather than soldering.

Furthermore, a control circuit may be formed over the printed circuit board 119 a and electronic parts or the like electrically connected to the control terminals 121 and 131 may be mounted over the printed circuit board 119 a. The printed circuit board 119 b described later has the same structure as the printed circuit board 119 a has, and is handled in the same way.

The above laminated substrate 140, printed circuit boards 119 a and 119 b, and terminal blocks 120 and 130 are prepared.

(Step S12) The case 110 is formed by integrally molding the printed circuit boards 119 a and 119 b over which the terminal blocks 120 and 130 are disposed, wiring terminals 116, 117, and 118, the P terminals 113 a, 113 b, and 113 c, the N terminals 114 a, 114 b, and 114 c, the U terminal 115 a, the V terminal 115 b, the W terminal 115 c, and the like by the use of resin.

The case 110 formed in this way will be described by the use of FIGS. 9 and 10.

FIG. 9 is a plan view of the case of the semiconductor device according to the first embodiment. FIG. is a rear view of the case of the semiconductor device according to the first embodiment.

The case 110 is formed by, for example, injection molding by the use of resin and has the shape of a frame in whose central area a concavity is formed. The housing portions 112 a, 112 b, and 112 c in which the above laminated substrates 140 are housed are formed in the concavity of the central area. The printed circuit boards 119 a and 119 b are disposed (in the lateral direction of the case 110) in peripheral portions of the housing portion 112 a. A pair of printed circuit boards 119 a are disposed (in the lateral direction of the case 110) in peripheral portions of the housing portion 112 b. The printed circuit boards 119 a and 119 b are disposed (in the lateral direction of the case 110) in peripheral portions of the housing portion 112 c. Furthermore, each printed circuit board 119 a or each printed circuit board 119 b is integrally molded with the case 110 and is disposed in the semiconductor device. A resin beam 111 a or 111 b made of resin is formed over a printed circuit board 119 a disposed in this way. The case 110 withstands pressure applied in the lateral direction of the case 110 by the resin beams 111 a and 111 b.

With the housing portion 112 a of the above case 110, the P terminal 113 a and the N terminal 114 a are formed on the side of one side in the longitudinal direction of the case 110 (on the lower side of the case 110 in FIG. 9) and the U terminal 115 a is formed on the side of the other side in the longitudinal direction of the case 110 (on the upper side of the case 110 in FIG. 9). Similarly, with the housing portion 112 b of the above case 110, the P terminal 113 b and the N terminal 114 b are formed on the side of one side in the longitudinal direction of the case 110 (on the lower side of the case 110 in FIG. 9) and the V terminal 115 b is formed on the side of the other side in the longitudinal direction of the case 110 (on the upper side of the case 110 in FIG. 9). Furthermore, with the housing portion 112 c of the above case 110, the P terminal 113 c and the N terminal 114 c are formed on the side of one side in the longitudinal direction of the case 110 (on the lower side of the case 110 in FIG. 9) and the W terminal 115 c is formed on the side of the other side in the longitudinal direction of the case 110 (on the upper side of the case 110 in FIG. 9).

The wiring terminals 116 electrically connected to the U terminal 115 a, the V terminal 115 b, and the W terminal 115 c are disposed in the housing portions 112 a, 112 b, and 112 c respectively. The wiring terminals 116 extend in parallel with the printed circuit boards 119 a and 119 b to this side of the wiring terminals 118 described later. Furthermore, the wiring terminals 117 electrically connected to the N terminals 114 a, 114 b, and 114 c are disposed in the housing portions 112 a, 112 b, and 112 c respectively. The wiring terminals 117 extend in parallel with the printed circuit boards 119 a and 119 b from the N terminals 114 a, 114 b, and 114 c to this side of the wiring terminals 116. Furthermore, the wiring terminals 118 electrically connected to the P terminals 113 a, 113 b, and 113 c are disposed in the housing portions 112 a, 112 b, and 112 c respectively. The wiring terminals 118 protrude from the P terminals 113 a, 113 b, and 113 c.

In addition, the terminal blocks 120 and 130 are disposed over the printed circuit boards 119 b and 119 a, respectively, on a U terminal 115 a side of the housing portion 112 a and the control terminals 121 and 131 are electrically connected to the printed circuit boards 119 b and 119 a respectively. The terminal blocks 120 and 130 are disposed near the U terminal 115 a, the V terminal 115 b, and the W terminal 115 c on the side in the longitudinal direction of the case 110.

The terminal blocks 120 and 130 are integrated with resin of the case 110 by integral molding. At secondary molding time the upper surfaces, the under surfaces, or the side surfaces (third surfaces) between the upper and under surfaces of the terminal blocks 120 and 130 are welded to the heated resin. As a result, the terminal blocks 120 and 130 are joined to the case 110. In the example of FIG. 9, the side surfaces of the terminal blocks 120 and 130 connect with the upper surfaces and under surfaces of the terminal blocks 120 and 130 respectively. Thermoplastic resin, such as polyphenylene sulfide (PPS), may be used as resin. When the terminal blocks 120 and 130 which hold the control terminals 121 and 131, respectively, are molded (primary molding), it is desirable to form the bodies of the terminal blocks 120 and 130 by the use of resin which is equal in kind to or the same as resin used for forming the case 110. Forming the bodies of the terminal blocks 120 and 130 and the case 110 by the use of resin materials of the same kind makes secondary molding easy.

In order to dispose part of the case 110 on an upper surface side of the level difference portions 123 and 133, at secondary molding time the level difference portions 123 and 133 are covered with resin and integral molding is performed. By doing so, the terminal blocks 120 and 130 and the case 110 may be joined firmly. The terminal blocks 120 and 130 and the case 110 are integrally molded so that the end portions of the control terminals 121 and 131 which are exposed or protrude on an under surface (second principal plane) side of the printed circuit boards 119 a and 119 b will be in contact with the case 110. By doing so, the printed circuit boards 119 a and 119 b are held (sandwiched) between the under surfaces (second surfaces) of the terminal blocks 120 and 130 and the case 110. As a result, the printed circuit boards 119 a and 119 b may be fixed firmly to the case 110. In addition, the following method may be used. Resin is poured into the spaces 122 and 132 of the terminal blocks 120 and 130 respectively. Part of the case 110 is disposed in the spaces 122 and 132, is joined to the terminal blocks 120 and 130, and is in contact with the control terminals 121 and 131. By adopting a sandwich structure, the printed circuit boards 119 a and 119 b adheres reliably to the case 110.

The printed circuit board 119 a integrally molded with the case 110 by primary molding will now be described by the use of FIG. 8.

FIG. 8 is a fragmentary sectional view of the printed circuit board and the laminated substrate of the semiconductor device according to the first embodiment.

FIG. 8 is a fragmentary sectional view taken along the dot-dash line X-X of FIG. 1. As illustrated in FIG. 8, an end portion of the printed circuit board 119 a projects from the case 110 into the inside of the housing portion (housing area) 112 a, that is to say, to a laminated substrate 140 side. The projecting end portion is formed as a result of sandwiching the printed circuit board 119 a by a metal mold at secondary molding time. Furthermore, as illustrated in FIGS. 6 and 7, the aligned electrodes 119 a 1 and through holes 119 a 2 of the printed circuit board 119 a are disposed along the projecting end portion.

In step S12, a case where the wiring terminals 116 and 117 are integrally molded at the time of forming the case 110 is taken as an example. However, the case 110 may be formed by integrally molding the components other than the wiring terminals 116 and 117. In this case, the wiring terminals 116 and 117 are joined at determined positions by welding after the case 110 is formed.

(Step S13) The laminated substrates 140 prepared in step S11 b are housed in the case 110 formed in step S12. The resin beams 111 a and 111 b are then attached over the printed circuit boards 119 a.

To be concrete, the laminated substrate 140 described in FIG. 3 is placed over a, for example, copper plate or a cooler. The case 110 is adhered to the laminated substrate 140 placed over the copper plate or the cooler so that the laminated substrate 140 placed over the copper plate or the cooler will be housed in each of the housing portions 112 a, 112 b, and 112 c of the case 110 described in FIGS. 9 and 10. At housing time the conductive terminal 143 b and the lead frame 145 a of the laminated substrate 140 are joined to (a back surface side of) the wiring terminal 116 of the case 110. Furthermore, the lead frame 145 b of the laminated substrate 140 is joined to (a back surface side of) the wiring terminal 117 of the case 110. In addition, the conductive terminal 143 a of the laminated substrate 140 is joined to (a back surface side of) the wiring terminal 118 of the case 110. After that, the resin beams 111 a and 111 b are attached over the printed circuit boards 119 a.

(Step S14) The control electrodes, such as gate electrodes, of the semiconductor chips 144 a, 144 b, and 144 c and the printed circuit board 119 a are connected by wires 148 and the control electrodes, such as gate electrodes, of the semiconductor chips 146 a, 146 b, and 146 c and the printed circuit board 119 b are connected by wires 148.

As a result, the structure of the semiconductor device 100 illustrated in FIG. 1 is obtained.

It is desirable to dispose the semiconductor chips 144 a, 144 b, and 144 c so that each control electrode will be aligned along the printed circuit board 119 a. The same applies to the semiconductor chips 146 a, 146 b, and 146 c. This disposition makes connection by the wires 148 easy. As illustrated in FIG. 3, the use of RC-IGBTs as the semiconductor chips 144 a, 144 b, 144 c, 146 a, 146 b, and 146 c makes alignment of the control electrodes easy.

(Step S15) The laminated substrates 140, the printed circuit boards 119 a and 119 b, the resin beams 111 a and 111 b, the wiring terminals 116, 117, and 118, the wires 148, and the like in the concavity of the case 110 are sealed by the use of sealing resin and the sealing resin is cured. As a result, the semiconductor device 100 is completed.

At this time resin may be poured into the spaces 122 and 132 of the terminal blocks 120 and 130, respectively, to seal the control terminals 121 and 131 in the spaces 122 and 132 with the resin. Performing sealing in this way makes adhesion of the control terminals 121 and 131 to the printed circuit boards 119 a and 119 b more reliable. In addition, when the terminal blocks 120 and 130 are sealed, the level difference portions 123 and 133 of the terminal blocks 120 and 130, respectively, may be covered with resin. By doing so, the terminal blocks 120 and 130 are pressed against the printed circuit boards 119 a and 119 b. As a result, adhesion of the control terminals 121 and 131 to the printed circuit boards 119 a and 119 b becomes more reliable. Accordingly, the positions of the level difference portions 123 and 133 are not limited to those illustrated in FIG. 4. There is no limit to the positions of the level difference portions 123 and 133 as long as they are formed on surfaces perpendicular to the surfaces of the terminal blocks 120 and 130 opposite the printed circuit board 119 a. Furthermore, each of the level difference portions 123 and 133 may be formed not only on one surface but also on plural surfaces. For example, epoxy resin may be used as the sealing resin.

Circuit structure in the above semiconductor device 100 will now be described by the use of FIGS. 1, 3, and 11.

FIG. 11 is a circuit diagram which illustrates circuit structure in the semiconductor device according to the first embodiment.

With the laminated substrate 140 in the housing portion 112 a of the semiconductor device 100 (FIGS. 1 and 3) the conductive terminal 143 a electrically connected to the P terminal 113 a via the wiring terminal 118 is electrically connected to the collector electrodes of the semiconductor chips 144 a, 144 b, and 144 c via the circuit board 142 a. The wiring terminal 116 is electrically wired to the lead frame 145 a electrically connected to the emitter electrodes of the semiconductor chips 144 a, 144 b and 144 c, and is electrically connected to the U terminal 115 a.

The conductive terminal 143 b is electrically connected to the wiring terminal 116 electrically connected to the U terminal 115 a, and is electrically connected to the collector electrodes of the semiconductor chips 146 a, 146 b and 146 c via the circuit board 142 b. The wiring terminal 117 is electrically wired to the lead frame 145 b electrically connected to the emitter electrodes of the semiconductor chips 146 a, 146 b and 146 c, and is electrically connected to the N terminal 114 a.

Furthermore, with the laminated substrate 140 in the housing portion 112 b of the semiconductor device 100 (FIGS. 1 and 3) the conductive terminal 143 a electrically connected to the P terminal 113 b via the wiring terminal 118 is electrically connected to the collector electrodes of the semiconductor chips 144 a, 144 b, and 144 c via the circuit board 142 a. The wiring terminal 116 is electrically wired to the lead frame 145 a electrically connected to the emitter electrodes of the semiconductor chips 144 a, 144 b and 144 c, and is electrically connected to the V terminal 115 b.

The conductive terminal 143 b is electrically connected to the wiring terminal 116 electrically connected to the V terminal 115 b, and is electrically connected to the collector electrodes of the semiconductor chips 146 a, 146 b and 146 c via the circuit board 142 b. The wiring terminal 117 is electrically wired to the lead frame 145 b electrically connected to the emitter electrodes of the semiconductor chips 146 a, 146 b and 146 c, and is electrically connected to the N terminal 114 b.

In addition, with the laminated substrate 140 in the housing portion 112 c of the semiconductor device 100 (FIGS. 1 and 3) the conductive terminal 143 a electrically connected to the P terminal 113 c via the wiring terminal 118 is electrically connected to the collector electrodes of the semiconductor chips 144 a, 144 b, and 144 c via the circuit board 142 a. The wiring terminal 116 is electrically wired to the lead frame 145 a electrically connected to the emitter electrodes of the semiconductor chips 144 a, 144 b and 144 c, and is electrically connected to the W terminal 115 c.

The conductive terminal 143 b is electrically connected to the wiring terminal 116 electrically connected to the W terminal 115 c, and is electrically connected to the collector electrodes of the semiconductor chips 146 a, 146 b and 146 c via the circuit board 142 b. The wiring terminal 117 is electrically wired to the lead frame 145 b electrically connected to the emitter electrodes of the semiconductor chips 146 a, 146 b and 146 c, and is electrically connected to the N terminal 114 c.

By adopting the above structure, the circuit illustrated in FIG. 11 is formed in the semiconductor device 100.

Therefore, in a state in which the positive electrode is connected to the P terminal 113 a and the negative electrode is connected to the N terminal 114 a, control signals are inputted from or outputted to external circuits via the control terminals 121 and 131 and the printed circuit boards 119 a and 119 b. The control signals are inputted to the gate electrodes of the semiconductor chips 144 a, 144 b, and 144 c and the semiconductor chips 146 a, 146 b, and 146 c via the printed circuit boards 119 a and 119 b and the wires 148. An output is obtained from the U terminal 115 a according to the control signals.

Furthermore, in a state in which the positive electrode is connected to the P terminal 113 b and the negative electrode is connected to the N terminal 114 b, control signals are inputted or outputted via the control terminals 121 and 131 and the printed circuit boards 119 a and 119 b. The control signals are inputted to the gate electrodes of the semiconductor chips 144 a, 144 b, and 144 c and the semiconductor chips 146 a, 146 b, and 146 c via the printed circuit boards 119 a and 119 b and the wires 148. An output is obtained from the V terminal 115 b according to the control signals.

In addition, in a state in which the positive electrode is connected to the P terminal 113 c and the negative electrode is connected to the N terminal 114 c, control signals are inputted or outputted via the control terminals 121 and 131 and the printed circuit boards 119 a and 119 b. According to these control signals, control signals are inputted to the gate electrodes of the semiconductor chips 144 a, 144 b, and 144 c and the semiconductor chips 146 a, 146 b, and 146 c via the printed circuit boards 119 a and 119 b and the wires 148. An output is obtained from the W terminal 115 c according to the control signals.

A semiconductor device other than the semiconductor device 100 will now be described as an example for reference by the use of FIG. 12.

FIG. 12 is a plan view of a semiconductor device taken as an example for reference.

A semiconductor device 300 includes a case 310 and three laminated substrates 320 housed in a housing portion 330 formed in a central area of the case 310.

The case 310 is formed by injection molding by the use of resin. Control terminals 311, control electrodes 312 electrically connected to the control terminals 311, P terminals 313 a, 313 b, and 313 c, N terminals 314 a, 314 b, and 314 c, a U terminal 315 a, a V terminal 315 b, and a W terminal 315 c are integrally molded.

The laminated substrate 320 includes a radiation plate (not illustrated) formed over an under surface of an insulating substrate 321 and circuit boards 322 a, 322 b, 322 c, 322 d, 322 e, and 322 f formed over an upper surface of the insulating substrate 321. In addition, semiconductor chips 323 a and 323 c and semiconductor chips 323 b and 323 d are disposed over the circuit boards 322 b and 322 f, respectively, with solder therebetween.

The above laminated substrate 320 is housed in the housing portion 330 of the case 310. The control electrodes 312, the circuit boards 322 a, 322 c, and 322 d, and main terminals of the semiconductor chips 323 a, 323 b, 323 c, and 323 d are connected by wires 324.

As illustrated in FIG. 12, with the above semiconductor device 300 wiring routing is performed from the control electrodes 312 electrically connected to the control terminals 311 to the circuit boards 322 c and 322 d in order to input control signals to the semiconductor chips 323 a, 323 b, 323 c, and 323 d. In addition, ten wires 324 are wired from each of the semiconductor chips 323 a, 323 b, 323 c, and 323 d. That is to say, wiring of wires 324 is complicated. Such wiring deteriorates assemble-ability and increases man-hours needed for wiring work. Furthermore, with wirings of a control signal system a magnetic field or the like produced at switching time has an influence on the characteristics of a product, depending on a routing method. As a result, a malfunction may occur.

With the semiconductor device 100, on the other hand, the printed circuit boards 119 a and 119 b are disposed in the peripheral portions of the housing portions 112 a, 112 b, and 112 c of the case 110 in which the laminated substrates 140 are housed. The terminal blocks 120 and 130 which hold the control terminals 121 and 131, respectively, that output control signals to the printed circuit boards 119 a and 119 b are disposed over the printed circuit boards 119 a and 119 b. The gate electrodes of the semiconductor chips 144 a, 144 b, and 144 c and the semiconductor chips 146 a, 146 b, and 146 c and the printed circuit boards 119 a and 119 b, respectively, are electrically connected by the wires 148.

This leads to wiring simplification in a control signal system of the semiconductor device 100. Accordingly, wiring routing and bundling are easily controlled. As a result, assemble-ability is improved and an increase in man-hours needed for wiring work is checked. Furthermore, complicated routing is avoided, mis-wiring is suppressed, and the number of parts, such as circuit patterns and electrode pads, is reduced. Accordingly, the semiconductor device 100 is miniaturized. In addition, because wiring simplification and consistency are realized in the control signal system of the semiconductor device 100, the influence of a magnetic field or the like produced at switching time on the characteristics of a product is alleviated and the occurrence of a malfunction is suppressed.

Second Embodiment

In a second embodiment another semiconductor device will be described by the use of FIG. 13.

FIG. 13 is a perspective view of a semiconductor device according to a second embodiment.

With a semiconductor device 200 a bus bar block 210 formed by integrally molding the wiring terminals 116 and 117 of the semiconductor device 100 according to the first embodiment (FIG. 1) is mounted in a concavity in the central area.

The structure except wiring terminals 116 and 117 of a case 110 of the semiconductor device 200 is the same as that of the case 110 of the semiconductor device 100. Laminated substrates 140 in the semiconductor device 200 are equal in structure to the laminated substrates 140 in the semiconductor device 100.

Furthermore, circuit structure in the semiconductor device 200 is equal to the circuit structure in the semiconductor device 100 according to the first embodiment (FIG. 11).

A method for fabricating the above semiconductor device 200 will be described by the use of FIG. 14.

FIG. 14 is a flow chart of a method for fabricating the semiconductor device according to the second embodiment.

(Step S21) Printed circuit boards 119 a and 119 b and terminal blocks 120 and 130 are prepared (step S21 a). Furthermore, the laminated substrates 140 are prepared (step S21 b). In addition, the bus bar block 210 is prepared (step S21 c). In step S21 a, control terminals 121 and 131 of the terminal blocks 120 and 130, respectively, are press-fitted in the printed circuit boards 119 a and 119 b to hold the printed circuit boards 119 a and 119 b on an under surface side of the terminal blocks 120 and 130.

The structure of the laminated substrates 140 (FIG. 3) and the structure of the terminal blocks 120 and 130 (FIGS. 4 through 7) are described in the first embodiment.

The bus bar block 210 will be described by the use of FIG. 15.

FIG. 15 is a plan view of the bus bar block of the semiconductor device according to the second embodiment.

The bus bar block 210 is formed by the use of resin. For example, more than one frame is combined into a framework so that it will fit into the concavity in the central area of the semiconductor device 200. In addition, for example, the wiring terminals 116 and 117 corresponding to housing portions 112 a, 112 b, and 112 c are integrally molded on a back surface side of the frames combined in this way.

(Step S22) The case 110 is formed by integrally molding the printed circuit boards 119 a and 119 b, the terminal blocks 120 and 130, wiring terminals 118, P terminals 113 a, 113 b, and 113 c, N terminals 114 a, 114 b, and 114 c, a U terminal 115 a, a V terminal 115 b, and a W terminal 115 c by the use of resin.

That is to say, the case 110 formed in step S22 corresponds to the case 110 in the first embodiment illustrated in FIGS. 9 and 10 from which the wiring terminals 116 and 117 and the resin beams 111 a and 111 b have been removed.

(Step S23) The laminated substrates 140 prepared in step S21 b are housed in the case 110 formed in step S22.

To be concrete, the laminated substrate 140 described in FIG. 3 is placed over a, for example, copper plate or a cooler. The case 110 is adhered to the laminated substrate 140 placed over the copper plate or the cooler so that the laminated substrate 140 placed over the copper plate or the cooler will be housed in each of the housing portions 112 a, 112 b, and 112 c of the case 110 formed in step S22. At this time a conductive terminal 143 a of the laminated substrate 140 in the housing portion 112 a is joined to the wiring terminal 118 electrically connected to the P terminal 113 a. A conductive terminal 143 a of the laminated substrate 140 in the housing portion 112 b is joined to the wiring terminal 118 electrically connected to the P terminal 113 b. A conductive terminal 143 a of the laminated substrate 140 in the housing portion 112 c is joined to the wiring terminal 118 electrically connected to the P terminal 113 c.

(Step S24) Semiconductor chips 144 a, 144 b, and 144 c and semiconductor chips 146 a, 146 b and 146 c and the printed circuit boards 119 a and 119 b, respectively, are connected by wires 148.

The connection by the wires 148 will now be described by the use of FIG. 16.

FIG. 16 is a plan view of the case of the semiconductor device according to the second embodiment in which insulating substrates are housed.

As illustrated in FIG. 16, gate electrodes of the semiconductor chips 144 a, 144 b, and 144 c and the printed circuit board 119 a are connected by the wires 148 and gate electrodes of the semiconductor chips 146 a, 146 b, and 146 c and the printed circuit board 119 b are connected by the wires 148.

(Step S25) The bus bar block 210 (FIG. 15) prepared in step S21 c is mounted in the concavity in the central area of the case 110 obtained in this way. The laminated substrates 140 are housed in the case 110 and the semiconductor chips 144 a, 144 b, and 144 c and the semiconductor chips 146 a, 146 b and 146 c and the printed circuit boards 119 a and 119 b, respectively, are connected by the wires 148. Next, the wiring terminals 116 are joined to conductive terminals 143 b and lead frames 145 a by welding and the wiring terminals 117 are joined to lead frames 145 b by welding.

At this time, in the housing portion 112 a, the wiring terminal 116 of the bus bar block 210 is electrically connected to the conductive terminal 143 b and the lead frame 145 a of the laminated substrate 140 and is electrically connected to the U terminal 115 a. Furthermore, the wiring terminal 117 of the bus bar block 210 is electrically connected to the lead frame 145 b of the laminated substrate 140.

Furthermore, in the housing portion 112 b, the wiring terminal 116 of the bus bar block 210 is electrically connected to the conductive terminal 143 b and the lead frame 145 a of the laminated substrate 140 and is electrically connected to the V terminal 115 b. Furthermore, the wiring terminal 117 of the bus bar block 210 is electrically connected to the lead frame 145 b of the laminated substrate 140.

In addition, in the housing portion 112 c, the wiring terminal 116 of the bus bar block 210 is electrically connected to the conductive terminal 143 b and the lead frame 145 a of the laminated substrate 140 and is electrically connected to the W terminal 115 c. Furthermore, the wiring terminal 117 of the bus bar block 210 is electrically connected to the lead frame 145 b of the laminated substrate 140.

The structure of the semiconductor device 200 illustrated in FIG. 13 is obtained in this way.

(Step S26) The laminated substrates 140, the printed circuit boards 119 a and 119 b, the wires 148, the bus bar block 210, and the like in the concavity of the case 110 are sealed by the use of sealing resin and the sealing resin is cured. As a result, the semiconductor device 200 is completed.

As has been described, with the semiconductor device 200 the printed circuit boards 119 a and 119 b are disposed in peripheral portions of the housing portions 112 a, 112 b, and 112 c of the case 110 in which the laminated substrates 140 are housed. The terminal blocks 120 and 130 which hold the control terminals 121 and 131, respectively, that output control signals to the printed circuit boards 119 a and 119 b are disposed over the printed circuit boards 119 a and 119 b. The gate electrodes of the semiconductor chips 144 a, 144 b, and 144 c and the printed circuit board 119 a are electrically connected by the wires 148 and the gate electrodes of the semiconductor chips 146 a, 146 b, and 146 c and the printed circuit board 119 b are electrically connected by the wires 148.

This leads to wiring simplification in a control signal system of the semiconductor device 200. Accordingly, wiring routing and bundling are easily controlled. As a result, assemble-ability is improved and an increase in man-hours needed for wiring work is checked. Furthermore, complicated routing is avoided, mis-wiring is suppressed, and the number of parts, such as circuit patterns and electrode pads, is reduced. Accordingly, the semiconductor device 200 is miniaturized. In addition, because wiring simplification and consistency are realized in the control signal system of the semiconductor device 200, the influence of a magnetic field or the like produced at switching time on the characteristics of a product is alleviated and the occurrence of a malfunction is suppressed.

Furthermore, with the semiconductor device 200 the wiring terminals 116 and 117 are fitted in the housing portions 112 a, 112 b, and 112 c only by mounting the bus bar block 210 having the wiring terminals 116 and 117 in the concavity in the central area of the semiconductor device 200. Therefore, the assemble-ability of the wiring terminals 116 and 117 is improved and man-hours needed for assembling the wiring terminals 116 and 117 are reduced. In addition, because the semiconductor device 200 includes the bus bar block 210, the rigidity is improved and deformation of the semiconductor device 200 by bending or twisting caused by shock from the outside or the like is small. This prevents shock, damage, or the like to the semiconductor chips 144 a, 144 b, and 144 c and the semiconductor chips 146 a, 146 b and 146 c in the semiconductor device 200.

According to the disclosed techniques, wiring connection is simplified.

All examples and conditional language provided herein are intended for the pedagogical purposes of aiding the reader in understanding the invention and the concepts contributed by the inventor to further the art, and are not to be construed as limitations to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although one or more embodiments of the present invention have been described in detail, it should be understood that various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention. 

What is claimed is:
 1. A semiconductor device comprising: a laminated substrate including an insulating board and a circuit board disposed over a front surface of the insulating board; a semiconductor chip disposed over the circuit board; a case having a shape of a frame that has a concavity formed in a central area thereof, the case having a housing area for housing the laminated substrate and the semiconductor chip, the housing area being formed in the concavity, the case being made of resin; external connection terminals each having a first end portion, a second end portion lower than the first end portion, and a body portion; and a printed circuit board having a first principal plane and a second principal plane opposite the first principal plane, disposed over a periphery of the housing area, electrically connected to a control electrode of the semiconductor chip by a connecting member, connected to the second end portions of the external connection terminals, and attached to the case, wherein the second principal plane of the printed circuit board is fixed to a front surface of the frame of the case by integral molding, a front surface of the semiconductor chip is located at a lower level than the first and second principal planes of the printed circuit board, and an end portion of the printed circuit board extends from the case toward the semiconductor chip inside the housing area.
 2. The semiconductor device according to claim 1, wherein: the printed circuit board has a wiring layer and a plurality of electrodes electrically connected to the wiring layer; and the plurality of electrodes are arranged over the printed circuit board along the projecting end portion of the printed circuit board.
 3. The semiconductor device according to claim 1, wherein: the printed circuit board has a plurality of through holes piercing from the first principal plane to the second principal plane; and the plurality of through holes have therein resin.
 4. The semiconductor device according to claim 3, wherein the second end potions of the external connection terminals are each press-fitted in one of the plurality of through holes of the printed circuit board.
 5. The semiconductor device according to claim 4, wherein the first and second end portions of the external connection terminals are thicker than the body portions of the external connection terminals.
 6. The semiconductor device according to claim 1, wherein: the semiconductor chip includes a plurality of semiconductor chips; the plurality of semiconductor chips are disposed over the circuit board of the laminated substrate along the printed circuit board; and control electrodes of the plurality of semiconductor chips are disposed along the printed circuit board and are electrically connected to the printed circuit board.
 7. The semiconductor device according to claim 6, wherein: the plurality of semiconductor chips each have a main electrode; and the semiconductor device further includes wiring terminals disposed along the printed circuit board and connected to the main electrodes of the plurality of semiconductor chips.
 8. A semiconductor device comprising: a laminated substrate including an insulating board and a circuit board disposed over a front surface of the insulating board; a semiconductor chip disposed over the circuit board; a case having a housing area for housing the laminated substrate and the semiconductor chip, the case being made of resin, the housing area being substantially rectangular including two first sides that are opposite to each other and two second sides that are opposite to each other; external connection terminals each having a first end portion, a second end portion lower than the first end portion, and a body portion; and a printed circuit board having a first principal plane and a second principal plane opposite the first principal plane, disposed over a periphery of the housing area, the second principal plane of the printed circuit board being fixed to a periphery of the case by integral molding, wherein the printed circuit board is disposed along one side of the housing area, said side being one of the first sides, the external connection terminals are disposed on the printed circuit board at one end thereof and at one of the second sides of the housing area, the printed circuit board is electrically connected to a control electrode of the semiconductor chip by a connecting member, a front surface of the semiconductor chip is located at a lower level than the first principal plane of the printed circuit board, and an end portion of the printed circuit board extends from the case toward an inside of the housing area.
 9. The semiconductor device according to claim 8, wherein the printed circuit board includes a first portion and a second portion that form a L-shape, the first portion being longer than the second portion, the first portion of the printed circuit board is disposed along said one first side of the housing area, and the external connection terminals are formed on the second portion of the printed circuit board.
 10. The semiconductor device according to claim 8, wherein the connecting member extends substantially in parallel to the second sides of the housing area.
 11. The semiconductor device according to claim 8, wherein the printed circuit board is disposed only along said side of the housing area. 